Generic Name

Labetalol Hydrochloride

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Classification

FDA Approved Indications

• Management of hypertension

Mechanism of Action

Labetalol is a non-selective beta-adrenergic antagonist with alpha-1 adrenergic blocking activity, which causes vasodilation and decreases blood pressure by reducing heart rate and peripheral resistance.

Dosage and Administration

Adult: Initial dose typically 100 mg twice daily, titrated based on response. Maximum dose may be up to 2400 mg/day in divided doses.

Pediatric: Not commonly used in pediatric populations; consult specific guidelines.

Geriatric: Dose adjustments may be necessary based on renal and hepatic function; start at lower doses.

Renal Impairment: Use caution; may require dose adjustment and monitoring.

Hepatic Impairment: Use with caution; hepatic function should be monitored.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Widely distributed; crosses the blood-brain barrier.

Metabolism: Extensively metabolized in the liver.

Excretion: Excreted in urine and bile.

Half Life: 3 to 6 hours.

Contraindications

• Asthma or other bronchospastic conditions
• Second- or third-degree heart block
• Cardiogenic shock

Precautions

• Use with caution in heart failure, renal impairment, hepatic impairment, and in patients with a history of depression. Monitor blood pressure, heart rate, and respiratory status regularly. Not recommended during pregnancy unless clearly needed; breastfeeding considerations should be discussed.

Adverse Reactions - Common

• Fatigue (Common)
• Dizziness (Common)
• Nausea (Common)
• Bradycardia (Less common)

Adverse Reactions - Serious

• Severe hypotension (Rare)
• Bronchospasm (Rare)
• Liver function abnormalities (Rare)
• Heart failure exacerbation (Rare)

Drug-Drug Interactions

• Other antihypertensives, like calcium channel blockers, nitrates, diuretics, which may enhance hypotensive effects.
• CYP2D6 inhibitors may affect the metabolism of labetalol.

Drug-Food Interactions

• Alcohol may enhance hypotensive effects.

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Instruct patient to take medication as prescribed and not to stop suddenly.
• Warn about possible side effects like dizziness, fatigue, and bronchospasm.
• Advise to rise slowly from sitting or lying position.
• Inform about possible interactions with other medications and the importance of reporting all current medications.

Special Considerations

Black Box Warnings:

• Use in caution in patients with asthma or other bronchospastic conditions.

Genetic Factors: CYP2D6 poor metabolizers may have increased plasma levels.

Lab Test Interference: May interfere with certain laboratory tests, including liver function tests.

Overdose Management

Signs/Symptoms: Severe hypotension, bradycardia, bronchospasm, loss of consciousness.

Treatment: Supportive care, IV fluids, atropine for bradycardia, vasopressors for hypotension, airway management as needed.

Storage and Handling

Storage: Store at room temperature, 20-25°C (68-77°F).

Stability: Stable under recommended storage conditions.